Hello, Jeff. Glad I found your channel. You know your stuff. I'm looking at upgrading my battery banks, house and starter. I wonder if I upgrade to Lithium, can I start with one battery and increase the bank later? This is due to cost, and the cost of upgrading items like charger, alternator, etc. The engine battery will be a flooded acid model. How can I charge two different type of batteries with the same charging equipment? The house bank will eventually have 3 batteries. Thank you. - Moses
One of the benefits of Lithium batteries, unlike your lead acid, you can install more to your bank later as required.
To keep all your batteries charging together and the lithium separate from the lead acid we use DC-DC chargers. https://www.pysystems.ca/shop/power/dc-to-dc-converter/